681394345 has 8 divisors (see below), whose sum is σ = 817821576. Its totient is φ = 545016576.

The previous prime is 681394277. The next prime is 681394349. The reversal of 681394345 is 543493186.

It can be written as a sum of positive squares in 4 ways, for example, as 162511504 + 518882841 = 12748^2 + 22779^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681394345 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681394349) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33249 + ... + 49681.

It is an arithmetic number, because the mean of its divisors is an integer number (102227697).

Almost surely, 2^681394345 is an apocalyptic number.

It is an amenable number.

681394345 is a deficient number, since it is larger than the sum of its proper divisors (136427231).

681394345 is a wasteful number, since it uses less digits than its factorization.

681394345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24731.

The product of its digits is 311040, while the sum is 43.

The square root of 681394345 is about 26103.5312745230. The cubic root of 681394345 is about 879.9665728522.

The spelling of 681394345 in words is "six hundred eighty-one million, three hundred ninety-four thousand, three hundred forty-five".